I cut a piece off, put rooting hormone on the end, and stick it in damp vermiculite. They like humidity, so put them under a dome (plastic bag works too) and keep checking that they don't start rotting (as in, if they get too warm). After a couple of weeks, they should have rooted, so then pot them up.

I usually plant petunia seeds in late February or early March.

If you have a good soilless mix like promixBX you can start them right in the soil.

Taking cuttings:
With a sharp knife or razor blade cut a 4 or 5 inch piece from the growing tip, cutting just below a leaf. All roots and branches come from a leaf joint. Remove the bottom leaves. Prepare your soilless mix. In a clean pail mix it with water. Squeeze a handful and just a little water should come out and then put it in your container. Dibble a hole with your finger or whatever. Dip about 1/2 inch of the cut end in rooting hormone. It comes in powder or gel, either is OK as long as it's for soft wood cuttings. I use Stim-root NO. 1. After it's dipped put it in the hole and cover it in, and you're done.

Keep the soil moist but not overly wet. They may look a bit wilted at first but that will change as it starts to grow roots. You will know it's rooted when it starts to show new growth.

I start my cuttings in the four pack containers you buy annuals in and then transplant into bigger containers when they are well rooted. It is easier to control moisture levels in a smaller container.

I start my Petunia seeds 7 or 8 weeks before planting outside.

Thanks to all, I might give it a short this coming year. C